Variable Frequency Drive Application Engineering Bulletin

Purpose: Variable frequency drives (VFDs) are an essential component in today’s modern applications of industrial refrigeration and commercial comfort cooling for evaporative condensers, evaporators, cooling towers, closed circuit coolers and other equipment. Proper operation of all the components of these systems is required to maintain the efficiency and reliability that’s expected of them and the VFD is no exception. This bulletin will explain the basic functions of the VFD, along with identifying potential issues related to its operation. In the following pages, recommendations for good VFD application practices will be presented along with accessory items that are designed to prevent motor failure and other operating issues.